Drill shaft buffer



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Jan. 19, 1932. P. BARCLAY' DRILL SHAFT BUFFER Filed Oct. l, 1928 Patented Jan. 19,1932

UNITED EDWARD PAUL BARCLAY, OF LOS ANGELES, CALIFORNIA DRILL SHAFT BUFFER Application filed october 1, 1928. Serial No. 309,443.

My invention relates to an improved drill sha-ft buffer and more particularly to a buffer which is adapted to protect the drill shaft or pipe and its joints from injurious Contact e' With well casing. Among the objects of my improvement is to provide a buffer which can easily be applied toa sectional drill shaft So as to protect its joints from contact with well casing either after the sections of the shaft have been assembled or as the sections are being joined and the shaft lowered into a well. Another object is to provide a buffer which can be applied for use without the assistance of any mechanical means and which when applied for use will remain fixed upon the shaft Without slipping up and down. A further object is to reduce cost and time .consumed in application of buffers to a drill shaft and to reduce friction and power required for drilling. A still further object is to provide an improved buffer which can be applied to a drill shaft without the necessity of breaking the shaft apart into its individual sections.

With these and other objects in view, my invention comprises the features of construction and combinations of parts hereinafter described and claimed.

In the accompanying drawings, forming a@ part of this specification, Fig. 1 is a cross section of a portion of a deep Well with a drill shaft equipped with my improved buffers; Fig. 2 is a plan of my improved buffer before it is applied for use; Fig. 3 is a section taken on the line 3 3 of Fig. 2; Fig. 4 is a section taken on the line 44 of Fig. 1; Fig. 5 is a section taken on the line 5 5 of F ig. 4, and

Fig. 6 is a side elevation of a detail of a drilly shaft showing one mannervin which the buffer C can be secured to the shaft.

ln the drawings 10 indicates the usual casing of an oil well and 11 the drill pipe or shaft made in sections and separately joined together by the usual joints 12 of slightly larger diameter than that of the body of the drill pipe and terminating in tapered threaded couplings 13. Upon this drill pipe is ,placed a series of my improved buffers A. The size of the buffers is greater than the eX- ternal diameter of the joints 12 and the buffers are placed at suitable intervals so as to protect the pipe from direct contact with the casing. The buffers are not however of sufficient diameter to vclose the casing against the free circulation of the usual mud laden liquid.

Each buicr consists of a single strip of suitable buffer material 14, which is wound spirally upon itself and upon the drill pipe as a core, close to the joints 12 or in any other suitable position. This strip as shown is eoncavo convex in cross section, excepting that portion which forms the inner wrap which is convex on its outer surface and straight on its inner surface, said straight 05 surface. merging into said concave surface at 18 (see Fig. 3). ln this manner when the strip is wound spirally upon itself using the drill pipe as a core a buffer is produced which curves cXteriorly up and down on the drill pipe, to produce a guiding buffer surface when the drill pipe is raised or lowered in the well. The inner and outer ends 15 and 16 of the strip 14 taper longitudinally to produce a smooth and even exterior surface on the buffer. As many wraps are cemented together and to the surface of the drill pipe to form a substantial buffer which will not 'unwind and loosen from the drill pipe. When desired the spiral convolutions of the buffer 30 may be vulcanized together and to the drill pipe to secure the parts together. A central longitudinal groove 19 in the inner surface of the strip and a corresponding rib 2() on the outer surface (see Fig. 4) intermesh and 85 serve to guide and hold the wraps of the strip in position with the side edges disposed evenly. The body of the strip may be made out of rubber or any other suitable material and the inner surface may be formed with an inelastic reinforcing fabric such as canvas 21, molded into the body of the strip. In this manner the buffer may be immovably secured to the pipe without stretching while the surface of the bufferis resilient to protect the pipe against impact and wearing the casing. The strip need not be made concavo convex in cross section within the spirit of my invention, it being obvious that it may be made of substantially even thickness throughout m0 its body portion and the buffer made substantially str i ht on its periphery vertically.

The buifr ma easily and quickly be assembled on the rill pipe without breaking down joints and when mounted in the manner stat-ed the buffers are prevented from slipping. When desired friction tape 22 may be wound spirally (see Fig. (l) around the drill pipe to secure the buffer thereon. The mud laden liquid in the well acts as a lubricant and the buffer reduces friction of the drill pipe against the casing. Excessive crookedness of the hole drilled is reduced by the luse of my improved buffers because of the guiding effect produced between the drill pipe and casing. These effects are particularly advantageous in deep drilling.

In accordance with the patent statutes, I have described the principles of operation of my invention together with the construction which I now consider to represent the best embodiment thereof but I desire to have it understood that the construction shown is only illustrative and that the invention can be carried out by other means and applied to uses other than those above set forth within the scope of the following claims.

Having described my invention what I claim as new and desire to secure by Letters Patent is:

1. A drill shaft buffer, comprising a strip of buffer material adapted for being Wound spirally about itself using the drill shaft as a core, said strip being formed with a longitudinal groove in one surface and a corresponding tongue on its opposite surface adapted to enter said groove When the strip is wound on said shaft and assist in holding the convolutions in place and said convolutions being secured together and to said shaft.

2. A drill shaft buffer comprising the combination with a drill shaft of a plurality of convolutions of buffer material Wrapped one upon another and provided with an arcuate outer periphery whereby the buffer is of maximum thickness at a point centrally of its ends and of minimum thickness at its ends.

3. A drill shaft butler comprising the combination with a drill shaft of a plurality of convolutions of buffer material wrapped one upon another and provided with an arcuate outer peripher whereby the buffer is of maximum thic ness at a point centrally of its ends and of minimum thickness at its ends, the innermost convolutions being vulcanized to the drill pipe and the outer convolutions being vulcanized together.

4. A drill shaft buffer comprising the combination with a drill shaft of a plurality of convolutions of buffer material wrapped one upon another and provided with an arcuate outer periphery whereby the buffer is of maximum thickness at'a oint centrally of its ends and of minimum t iickness at its ends, and

means formed on adjacent convolutions for inter-locking the convolutions.

5. A drill shaft buffer comprising in combination with a drill shaft, a buffer formed of resilient material spirally wound on the drill shaft, said convolutions being of gradually increasing thickness from the ends thereof inwardly for rovidin a buffer of maximum thickness mterme late its ends, and means formed on adjacent convolutions for interlocking the convolutions, said convolutions beinv vulcanized to said drill shaft and to each other.

6. A buffer for drill shafts formed of a plurality of spirally wound convolutions adapted to be wound upon a drill shaft and provided with a longitudinal opening therethru, the outer periphery of said buffer being tapered from its center outwardly to the ends to provide a lano-convex cross section, for the purpose escribed.

7. A buffer for drill shafts comprising a strip of buffer material wound spirally around a drill shaft, said strip being concavoconvex in cross section except that portion which forms the inner wrap, the inner surface of which portion being straight to fit the drill shaft, and the outer surface of said portion being convex to fit the concave inner surface of the adjacent Wrap.

In Witness whereof I have signed my name to this specification.

EDWARD PAUL BARCLAY. 

